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Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer

(1) The TBX2 subfamily of transcription factors (TBXs 2, 3, 4 and 5) are markedly down-regulated in human non-small cell lung cancer (NSCLC) and exert tumor suppressor effects in lung malignancy. Yet, mechanisms underlying suppressed expression of the TBX2 subfamily in NSCLC are elusive. Here, we in...

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Autores principales: Nehme, Eliana, Rahal, Zahraa, Sinjab, Ansam, Khalil, Athar, Chami, Hassan, Nemer, Georges, Kadara, Humam
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429281/
https://www.ncbi.nlm.nih.gov/pubmed/30866410
http://dx.doi.org/10.3390/ijms20051159
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author Nehme, Eliana
Rahal, Zahraa
Sinjab, Ansam
Khalil, Athar
Chami, Hassan
Nemer, Georges
Kadara, Humam
author_facet Nehme, Eliana
Rahal, Zahraa
Sinjab, Ansam
Khalil, Athar
Chami, Hassan
Nemer, Georges
Kadara, Humam
author_sort Nehme, Eliana
collection PubMed
description (1) The TBX2 subfamily of transcription factors (TBXs 2, 3, 4 and 5) are markedly down-regulated in human non-small cell lung cancer (NSCLC) and exert tumor suppressor effects in lung malignancy. Yet, mechanisms underlying suppressed expression of the TBX2 subfamily in NSCLC are elusive. Here, we interrogated probable epigenetic mechanisms in suppressed expression of the TBX2 subfamily in human NSCLC. (2) TBX2 subfamily gene expression and methylation levels in NSCLC and normal lung tissues were surveyed using publicly available RNA-sequence and genome-wide methylation datasets. Methylation β-values of the four genes were statistically compared between NSCLCs and normal lung tissues, correlated with gene expression levels, and interrogated with clinicopathological variables. Expression and methylation levels of TBXs were quantified in NSCLC cells using real-time PCR and methylation-specific PCR assays, respectively. Effects of the DNA methyltransferase inhibitor 5-azacytidine (Aza) on TBX2 subfamily expression were assessed in NSCLC cells. Impact of TBX2 subfamily expression on Aza-treated cells was evaluated by RNA interference. (3) All four TBXs were significantly hypermethylated in NSCLCs relative to normal lung tissues (p < 0.05). Methylation β-values of the genes, with exception of TBX2, were significantly inversely correlated with corresponding mRNA expression levels (p < 0.05). We found no statistically significant differences in hypermethylation levels of the TBX2 subfamily by clinicopathological features including stage and tobacco history. Expression levels of the TBX genes were overall suppressed in NSCLC cells relative to normal alveolar cells. Members of the subfamily were significantly hypermethylated in all tested NSCLC cell lines relative to normal alveolar cells. Treatment with Aza induced the expression of the TBX2 subfamily concomitant with NSCLC cell growth inhibition. Further, simultaneous knockdown of the four TBX genes markedly reduced anti-growth effects of Aza in NSCLC cells. (4) Our study sheds light on new epigenetic profiles in the molecular pathogenesis of human NSCLC.
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spelling pubmed-64292812019-04-10 Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer Nehme, Eliana Rahal, Zahraa Sinjab, Ansam Khalil, Athar Chami, Hassan Nemer, Georges Kadara, Humam Int J Mol Sci Article (1) The TBX2 subfamily of transcription factors (TBXs 2, 3, 4 and 5) are markedly down-regulated in human non-small cell lung cancer (NSCLC) and exert tumor suppressor effects in lung malignancy. Yet, mechanisms underlying suppressed expression of the TBX2 subfamily in NSCLC are elusive. Here, we interrogated probable epigenetic mechanisms in suppressed expression of the TBX2 subfamily in human NSCLC. (2) TBX2 subfamily gene expression and methylation levels in NSCLC and normal lung tissues were surveyed using publicly available RNA-sequence and genome-wide methylation datasets. Methylation β-values of the four genes were statistically compared between NSCLCs and normal lung tissues, correlated with gene expression levels, and interrogated with clinicopathological variables. Expression and methylation levels of TBXs were quantified in NSCLC cells using real-time PCR and methylation-specific PCR assays, respectively. Effects of the DNA methyltransferase inhibitor 5-azacytidine (Aza) on TBX2 subfamily expression were assessed in NSCLC cells. Impact of TBX2 subfamily expression on Aza-treated cells was evaluated by RNA interference. (3) All four TBXs were significantly hypermethylated in NSCLCs relative to normal lung tissues (p < 0.05). Methylation β-values of the genes, with exception of TBX2, were significantly inversely correlated with corresponding mRNA expression levels (p < 0.05). We found no statistically significant differences in hypermethylation levels of the TBX2 subfamily by clinicopathological features including stage and tobacco history. Expression levels of the TBX genes were overall suppressed in NSCLC cells relative to normal alveolar cells. Members of the subfamily were significantly hypermethylated in all tested NSCLC cell lines relative to normal alveolar cells. Treatment with Aza induced the expression of the TBX2 subfamily concomitant with NSCLC cell growth inhibition. Further, simultaneous knockdown of the four TBX genes markedly reduced anti-growth effects of Aza in NSCLC cells. (4) Our study sheds light on new epigenetic profiles in the molecular pathogenesis of human NSCLC. MDPI 2019-03-07 /pmc/articles/PMC6429281/ /pubmed/30866410 http://dx.doi.org/10.3390/ijms20051159 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Nehme, Eliana
Rahal, Zahraa
Sinjab, Ansam
Khalil, Athar
Chami, Hassan
Nemer, Georges
Kadara, Humam
Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title_full Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title_fullStr Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title_full_unstemmed Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title_short Epigenetic Suppression of the T-box Subfamily 2 (TBX2) in Human Non-Small Cell Lung Cancer
title_sort epigenetic suppression of the t-box subfamily 2 (tbx2) in human non-small cell lung cancer
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429281/
https://www.ncbi.nlm.nih.gov/pubmed/30866410
http://dx.doi.org/10.3390/ijms20051159
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